In windows of vehicles such as trains and cars, it is general that a plate glass is mounted on a metal vehicle body using a resin frame.
In recent years, a resin frame is molded directly onto a plate glass by an extrusion molding or injection molding of a resin in a condition having fluidity, and a glass with a frame, in which the frame and the plate glass are in one-piece, is used as a component for assembling vehicles.
In the case of producing a glass with a frame by injection molding, as shown in FIG. 19, plate glass 93 is retained between upper die 91 and lower die 92, and cavity 94 for frame is formed at a peripheral portion of plate glass 93. A resin in melted condition is injected into this cavity 94 for frame. After solidification of the resin in melted condition injected into cavity 94 for frame, upper die 91 is taken away, a glass with frame, in which the frame has been molded to be integral with the plate glass, is taken out of lower die 92, thereby producing the glass with frame.
In the case of molding a frame by injection molding to be integral with a plate glass, there is a problem in which the plate glass breaks by pressure of a melted resin flowing in the cavity of the die. To solve this breakage problem, it is disclosed in Patent Publication 1 that a frame is prepared by injection molding using a dummy plate, and the prepared frame is taken out of the dummy plate and then is bonded to a plate glass.
A method like that of Patent Publication 1, in which a frame is molded by using a dummy plate, then the frame is taken out of the dummy plate, and the frame taken out is mounted on a plate glass, is problematic in productivity.
Other than such preparation of a glass with frame, in the case of a resin molding by injecting a resin in melted condition into a die, a resin in melted condition injected into a cavity for frame flows by split flows. When the resins that have flowed by split flows join together, it is known that a defect portion of the surface that is called a weld line and becomes problematic in external appearance is formed at confluence position.
In order to prevent the occurrence of a defect of weld line, a technique is disclosed in Patent Publication 2 that a resin receiver is provided to disturb orientation of the resin or filler at weld line.
It is disclosed in Patent Publication 3 that, after a cavity is filled with a resin, the resin is moved into a resin receiver that is openable and closable and is provided in the vicinity of the confluence position, thereby moving the resin around the weld line.
Furthermore, in the case of molding a frame to be integral with a plate glass by injection molding, there occurs a defect, such as unevenness or sink, by contraction at a relatively thick portion of the frame, when the resin in melted condition solidifies by cooling.
It is disclosed in Patent Publication 4 that a pressurized gas is introduced into an injected resin. According to the method of injecting a pressurized gas, it is quite difficult to eliminate unevenness or sink on the frame surface, depending on the form of the section of the frame.
Patent Publication 1: Japanese Patent Application Publication 5-057797
Patent Publication 2: Japanese Patent Application Publication 5-285990
Patent Publication 3: Japanese Patent Application Publication 7-227888
Patent Publication 4: Japanese Patent Application Publication 11-170303